What's OSE.exe doing on my task manager?

Answer 1

You can look up any process at Process Library (http://www.processlibrary.com/)

This the information given by Process Library

ose.exe is a process belonging to the Microsoft Office Suite which adds additional installation support during CD install and web updates. This program is important for the stable and secure running of your computer and should not be terminated.
Scan Your PC including ose.exe to Detect any Security Threat. Not a critical component, but see the information above before disabling it.

Answer 2

OSE.exe is the software that enables Microsoft Office to check for and receive updates from the MS Office Update site.

You can disable the process in the Services module of your Administrative Tools. is the required navigation in Windows 2000 or XP.